package com.lgy.springcloud.loadbalance.impl;

import com.lgy.springcloud.loadbalance.MyLoadBanlance;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

@Component
public class MyLBImpl implements MyLoadBanlance {
    private AtomicInteger atomicInteger = new AtomicInteger(0);
    @Override
    public ServiceInstance serviceInstance(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement()%serviceInstances.size();
        return serviceInstances.get(index);
    }

    private final int getAndIncrement() {
        int current;
        int next;
        do{
            current = this.atomicInteger.get();
            next = current >= 2147483647 ? 0 : current+1;
        }while (this.atomicInteger.compareAndSet(current,next));
        return next;
    }
}
